#' @param multilevel Numeric, design matrix for repeated measurement analysis,
#'   where multilevel decomposition is required. For a one factor decomposition,
#'   the repeated measures on each individual, i.e. the individuals ID is input
#'   as the first column. For a 2 level factor decomposition then 2nd AND 3rd
#'   columns indicate those factors. See examples<%= multilevel.example %>
